Hundreds of students gathered outside the smouldering remains of a school in the Bangladeshi capital on Tuesday to demand answers after a military jet slammed into the campus, killing dozens of children.

A Bangladeshi military training aircraft crashed into the campus of a school in Dhaka, killing the pilot and at least 19 others, mostly students, officials say.

The F-7 BGI training jet crashed in the capital Dhaka on Monday after experiencing a technical problem shortly after take-off, a military spokesperson said.